This invention relates to balance beam weighing scales and is particularly adapted for use as a low-cost beam balance weighing scale for schoolroom use.
Beam balance weighing scales are well-known and typically include a base having a fulcrum transversely arranged along the longitudinal axis at the midpoint thereof, a beam balance supported on the fulcrum, and a pair of balance pans supported on the beam balance at opposite ends thereof. A pointer is typically attached to the beam and cooperates with a scale secured to the base to provide a visible zero balance indication. In use, an object of unknown weight is placed in one of the balance pans and test weights are added to the other balance pan until the beam pointer indicates a zero balance condition.
Although precision beam balance weighing scales of excellent design are well-known, their delicate nature and relatively high cost render them unsuitable for most schoolroom applications in which the persons operating the scales are students who are relatively unskilled in the operation of such devices. Although beam balance weighing scales have been designed for schoolroom use, such scales have been found deficient in one or more respects. Some are inexpensive to fabricate but are fragile or grossly inaccurate. Others are rugged and relatively accurate, but expensive. None combines the desiderata of simplicity, low cost and substantial accuracy.